Bought a SLX groupset to put on my 20 year old Kona hardtail and am having problems setting up the front mech. The BB is 68mm. SLX triple mech and chainset. Bar shifter is set to 3sp mode.

The chain happily sits on the small ring but when I push the shifter once it moves onto and past the middle ring and tries to get on the big ring. If I shift again then it goes over the big ring and off.

Clearly I can tighten the limiting screw to stop it going off but all that happens then is that it constrains the shifter from properly clicking into the top position.

I’ve also slackened the cable to the extent that it’s well floppy when in the small ring. But even then when I shift up it shifts too far.

To my novice eye, it seems almost as if the chainset is sitting too close to the seat tube, ie further left than the mech expects it to be. The mech is essentially pushing too far right.

Which would maybe suggest that I need more spacers on the right hand side of the BB. I put one on the left and two on the right, like wot it said on the awful instructions on the SHimano site.

any ideas?

cheers

Take it to a bike shop? They’ll put it right.

Did you start with no cable on mech and set low limit screw so just missing chain on lowest gear ? If you did that, then attached cable and then, without using shifter, pull cable by hand (pull out from down or seat tube depending how its routed and set high limit, for highest gear , it should be fine, although will need indexing. If you did all that then I dunno !

Depends on the mech type, but on some, it’s possible to route the cable into it’s clamp incorrectly, and mess up the pull ratio. A model no. may help identify if this is the problem.

Ditch the front mech et voila

I had exactly the same thing with a 10sp SLX front mech and 10sp XT front shifter. Couldnt’ get it to work properly at all without loads of slack cable when in granny.
Strange thing is, I put an old XT 9sp front mech on and it all worked perfectly with the new shifter! 🙄

Still dont know what was wrong with the 10sp one, and have since gone 1×10 so probably will never find out!

(sorry, I dont think that actually helps you!)